90 Mustang 3-2 port p/v conversion questions

Blown90LX

New Member
Jan 11, 2002
26
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1
Plymouth, MI
Hi,
I have a question for anyone who has performed a rear disc brake conversion and used an SN95 proportioning valve in place of the original unit. I purchased the brake booster, m/c and p/v from 95mustang (w/ rear disc brakes) and am unclear if I need to perform the 3-2 conversion presented in the technical description from (ttp://svo73mm.cjb.net/). The specific difference is the p/v from the 95 has a 3rd port in the back (facing the firewall) that I believe will prevent me from needing to perform the 3-2 conversion to the p/v. I believe I can just re-route the driver side front brake line to that 3rd port instead of creating an additional 3rd port with a "T" fitting as described in the directions at the link above. Anybody have any experience with this?

Attached is a pictures of the original unit (with a bolt in the back) and the unit from the 95 that has a cut-off brake line in it.
 

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My last Mustang had 4 wheel disk brakes and I got all the how to do it info from 87-93 Mustang 5.0 Brake upgrade pages. Improve your 60-0 times!

The SN 95 valve will not have the correct bias due to the difference in weight and weight distribution between a 5.0 Fox body and a SN95 body. Use an adjustible Wildwood or FMS proportioning valve. See Fox Body Mustang MC and PV Upgrades

See Wilwood 260-8419 - Wilwood Brake Proportioning Valves - summitracing.com for the wildwood proportioning valve, cost is $42.
 
Gut the stock fox valve and use an adjustable prop valve.

Toss the SN95 valve out. It's not the correct bias for your vehicle


+1 Do Not Use The sn95 Prop. Valve You Need An Adjustable valve

Heres Mine:
6264.jpg





You need to remove the plug on the front of your stock fox proportioning valve and pull out everything inside(i think theres a spring in there and a plunger)

you also need to get a new plug for the front of the valve that is solid without the hole in the middle.

Factory Plug: I stripped this out right away with 6pt. socket, felt like very soft metal had to use vise grips to get it off
6266.jpg


This is the solid plug, was like $20 from 50 resto, you have to use the o-ring from the stock plug
6265.jpg



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Much Appreciation!

Thanks for all of the feedback related to this conversion. I did forget to mention that I will be installing a manual proportioning valve & fully plan to gut the original as outlined at Matt Bobbit's site. Regarding the bias between the SN95 and fox bodied p/v, they look exactly the same expect for the 3 rd port on the SN95 (facing the firewall). If the valve is gutted, wouldn't the aftermarket p/v resolve the bias issue?
 
If you gut the SN95 plug, it would be the same thing.


My assumption was you were going to run the SN95 plug as is and resort to using the factory prop valve to control bias.


BTW, the valve is actually a combination valve as it contains a prop valve AND a shuttle valve in the rear. Some people delete the entire combination valve and run the lines straigh. This is a bad idea because the shuttle valve is a safety feature which help you stop the car if you suffer a catastrophic failure in the front or rear brakes
 
If you gut the SN95 plug, it would be the same thing.


My assumption was you were going to run the SN95 plug as is and resort to using the factory prop valve to control bias.


BTW, the valve is actually a combination valve as it contains a prop valve AND a shuttle valve in the rear. Some people delete the entire combination valve and run the lines straigh. This is a bad idea because the shuttle valve is a safety feature which help you stop the car if you suffer a catastrophic failure in the front or rear brakes

Only if you use a single chamber MC. If you use an older style dual chamber MC, the front and rear brakes are isolated by the MC. :nice:
 
Almost Completed

OK - I was able to locate all of the fittings described in Matt Bobbit's diagram and piece together the 3-2 conversion. I found everything at a pretty well stocked hardware (S&W Hardware in Plymouth MI) and short of it being in brass, it's exactly the same as the $30.00 kit sold through Maximum Motorsports for about $13.00. I scored the M-2450-A plug at Dallas Mustang (for $7.99 - $15.00 for shipping "You can pay me now or pay me later") so that should be arriving this week. Thanks again for all the input contributed to this conversion, I'm very greatful!!
Best Regards

Peter B
 

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